Abstract

The purpose of this study was to investigate activity of hip adductor muscles over time and during a representative crank cycle in fatiguing pedaling. Sixteen healthy men performed incremental pedaling exercise until exhaustion. During the exercise, surface electromyogram (EMG) was detected from adductor magnus (AM), adductor longus (AL), and selected thigh muscles. Temporal changes to normalized EMG in AM muscle resembled those in vastus lateralis (VL) muscle, whereas those in AL muscle showed later onset of increase from baseline compared with AM and VL muscles. During a representative crank cycle, the same level of normalized EMG was found between propulsive and pulling phases for AM muscle, whereas muscle activation of AL muscle during the pulling phase was statistically significant higher than that during the propulsive phase. We concluded that AM and AL muscles were gradually recruited over time during fatiguing pedaling exercise, but their temporal change and activation phases were not completely the same.

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Acknowledgments

This research was supported in part by a Grant-in-Aid for Scientific Research (#17300207) from the Japanese Ministry of Education, Science, Sports and Culture. The authors thank Dr. Masaaki Hirayama of Department of Neurology, Nagoya University Graduate School of Medicine and Dr. Teruhiko Koike of Research Center of Health, Physical Fitness & Sports, Nagoya University for their technical support and helpful suggestion of needle EMG recording.